Electronic consumption meters are delicate equipment that will suffer when placed in harmful environments, unless sensitive parts are well protected. The main cause of dysfunction is due to corrosion of the electronic circuit or the components.
As an example, an electronic meter for cold water is exposed to condensing water from the surrounding air, due to the temperature difference between the water in the meter and the potentially humid air. Other potentially harmful components in the environment could be aggressive gases or dust. An electronic water meter is also in risk of being dysfunctional, if water from the flow channel penetrates the barrier between the flow channel and the electronics.
Several known ways exist for protecting sensitive electronics in an ultrasonic consumption meter, which will be discussed below
Hermetically sealed box for the electronics with sealed electrical connections between the transducers and the electronics. This is an effective solution, but unfortunately it is very costly, as sealed electrical connections are complex to manufacture.
Potted electronics with or without potted transducers (an example is shown in EP1983311). This is not a very effective solution for long-term exposure of moisture or water, as known materials for potting of electronics has a relatively high degree of vapor penetration. A water meter is typically used for many years, and in some cases it will even be submerged in water for very long periods. Thus the risk of damage to the meter is high in these conditions.
Multilayer protection of electronics and transducers (an example is shown in EP2083251). This can be effective in some applications, but it is complex and expensive.
Thus it is an objective to provide a cost-effective ultrasonic based consumption meter in which the sensitive parts are effectively protected against water and other harmful substances. Other parameters to take into consideration are the strength and durability of the meter, in particular the flow channel and the connections to connecting tubes such as treads.